The present invention relates generally to fasteners and more particularly to a metal piercing fastener with an optimally resilient securing member carried by the body of the fastener and adapted to be accommodated within a void provided within the body of the fastener.
Fastener designs for securing work pieces together, such as, for example, a top laminate non metal work piece to a bottom light-gauge metal substrate (18 gauge and thinner) or alternatively, a light-gauge metal work piece to light-gauge metal substrate have generally been accomplished by threaded fasteners. The helical design of the thread has been successful in pulling the top laminate materials together tightly with the light-gauge metal substrate. Additionally, the helical thread design has provided sufficient withdrawal resistance to achieve performance values acceptable to industry. However, installation of helical threaded fasteners has proven time-consuming and fatiguing to the installer. The industries using these light-gauge metals require a fastener that has the speed of pneumatic nailing systems with the gripping and clamping features of helical-thread fasteners.
Nail-like products (hardened pins) have been used successfully in attaching work pieces (including top metals) to heavier gauge metal substrates (16 gauge and thicker). However, when the metal substrate is of light-gauge metal (18 gauge and thinner) or two or more pieces of light-gauge metal (18 gauge and thinner) are to be joined together, the substrate may be pushed away (deflection) from the top piece before the penetration and fastening process is completed. Additionally, the thinness of these metals is such that it creates situations where there is insufficient material to provide a friction-lock for current state-of-the-art pins. Whether they incorporate barbs, protrusions, undercuts, cross-hatching or spiral threads, these hardened pins lack withdrawal resistance when installed in these light-gauge materials. Additionally, they lack the ability to pull the substrate and the work piece together to close the gap between them caused by the deflection when the metal substrate of light-gauge metal is pushed away by penetration forces.
L. H. Flora (U.S. Pat. No. 2,740,505), discloses a one-piece, spring steel roofing nail for attaching insulation to a sheet metal deck. This roofing nail incorporates a center tongue within a cutout of the body, a point for piercing the light-gauge metal deck, and a head, bent in an angle from the same material as the body, used for clamping of the insulation layer. The center tongue is bent or deformed along its horizontal plane. This deformation is used to create a cam action to move the tongue within the pierced hole in the metal deck when the roofing nails are seated by successive hammer blows. The tongue protrudes through the hole with opposite flat surfaces thereof engaging opposite marginal edges of the hole and thus rely upon a wedge created by these two points to lock the nail in place. The main problem with this design is the lack of positive engagement of the tongue within the hole. Relying upon the smooth, radius area of the horizontal cam deformation of the tongue is unsuccessful and does not provide a positive locking means that meets industry standards to resist withdrawal forces. Such was recognized by Flora and referred to in his continuation-in-part, U.S. Pat. No. 2,751,052.
L. H. Flora (U.S. Pat. No. 2,751,052) discloses essentially the same structure as Flora U.S. Pat. No. 2,750,505 but with the center tongue extending completely through the pierced hole with the end of the tongue contacting the underside of the metal deck to provide a positive lock. The tight clamping of the insulation to the light-gauge metal deck is dependent upon the relatively soft porous and somewhat compressible insulation expanding from its compressed condition under the head when the nail is driven only to a predetermined depth as established by side stops. Although the tongue end engaging the underside of the metal deck improves withdrawal resistance, the structure of the nail precludes its use in substantially non-compressible materials and materials of different manufacturing thickness as well as manufacturing tolerances.
Dimas (U.S. Pat. No. 3,983,779) discloses a roofing nail designed to correct flaws in prior art roofing nails including the Flora design. The Dimas roofing nail is made substantially upon Flora""s original design with one or more tangs deformed along a horizontal plane, engaging the underneath of the bottom light-gauge metal deck. A protrusion is provided which leads the tang(s) to provide a pilot slot through which the tang(s) passes. This pilot slot solves a problem of prior art tongues or tangs becoming weakened or destroyed when passing through the pierced hole. The reason that the prior art tongues or tangs were weakened or destroyed is that they were substantially non-resilient. The Dimas improvement of Flora, by enlarging the hole for tang(s) passage, allows the possibility of the tang(s) coming lose and returning back through the enlarged hole if there is lateral movement or vibration to the wall or roof (which is common in buildings).
A fastener for securing a work piece to a metal substrate comprising an elongated body including a crown portion, a tip portion adapted to penetrate the substrate and form an opening therein, and at least one internal void disposed between the crown and tip portions, the elongated body having a thickness dimension; and at least one securing member having a thickness which is less than that of said body carried by the elongated body between the crown and tip portions and having side edges and adapted to grip and lock the work piece to the substrate after penetration, the securing member being adapted to be accommodated in the internal void and having a longitudinal axis, the securing member being deformed about its longitudinal (vertical) axis to cause said side edge(s) to extend outwardly from said body to ensure positive locking to the substrate within the pierced hole.